Vizier Guard
PYPI · VIZIER-GUARD · SCANNED SEP 20
Deterministic authorization and security guard for AI agent actions with signed receipts.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score → Why this is hard to score →
Supply Chain Security100
- No malware found by supply-chain analysis.Pass
- No known CVEs affecting this package version or its production dependencies.Pass
- Runs setuptools.build_meta at install time, a recognised native-build step with no shell scripting around it. View diagnostics → Pass
- No production dependencies, so there is no dependency health to assess. View diagnostics → Pass
Provenance & Transparency48
- Source repository is publicly reachable at the declared URL. View diagnostics → Pass
- Provenance check failed: no build-provenance attestation is published. See how to fix → View diagnostics → Fail
- Clear OSI-approved license (Apache-2.0).Pass
- Actively maintained (last published 7 days ago).Pass
- Publishes a security disclosure policy (SECURITY.md).Pass
Schema Quality & AI Usability77
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 417 tokens (~139/item across 3 items; 3 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management27
- Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 3 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 4 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities20
- Spec-recency check failed: implements MCP spec 2024-11-05; the latest is 2026-07-28. See how to fix → Fail
How do I install the Vizier Guard MCP server?
Vizier Guard runs locally as a PyPI package, launched with uvx vizier-guard. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
pypi · vizier-guard
claude mcp add vassiliylakhonin-vizier-guard -- uvx vizier-guard
{
"mcpServers": {
"vassiliylakhonin-vizier-guard": {
"command": "uvx",
"args": [
"vizier-guard"
]
}
}
} {
"servers": {
"vassiliylakhonin-vizier-guard": {
"command": "uvx",
"args": [
"vizier-guard"
]
}
}
} codex mcp add vassiliylakhonin-vizier-guard -- uvx vizier-guard
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"vassiliylakhonin-vizier-guard": {
"type": "local",
"command": [
"uvx",
"vizier-guard"
],
"enabled": true
}
}
} openclaw mcp add vassiliylakhonin-vizier-guard --command uvx --arg vizier-guard
mcp_servers:
vassiliylakhonin-vizier-guard:
command: "uvx"
args: ["vizier-guard"] {
"McpServers": {
"vassiliylakhonin-vizier-guard": {
"Transport": "stdio",
"Command": "uvx",
"Arguments": [
"vizier-guard"
]
}
}
} assistant mcp add vassiliylakhonin-vizier-guard -t stdio -c uvx -a vizier-guard
{
"mcpServers": {
"vassiliylakhonin-vizier-guard": {
"command": "uvx",
"args": [
"vizier-guard"
]
}
}
} Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 20 Sept 26 +4
- Stability: unverified → 0.27 ▲ functional
- 18 Sept 26 +15
- Malware scan: unverified → pass ▲ security
- 16 Sept 26 0
- Security disclosure: fail → pass ▲ functional
- 15 Sept 26 −15
- Malware scan: pass → unverified ▼ security
- 14 Sept 26 +15
- Malware scan: unverified → pass ▲ security
- 13 Sept 26 −15
- Malware scan: pass → unverified ▼ security
- 12 Sept 26 68
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 20 Sept 2026 · Analysed pypi/vizier-guard@0.3.2
Provenance No attestation
The registry publishes no build provenance for this version, so there is nothing to verify.
| Result | No attestation |
|---|---|
| Ecosystem | pypi |
Background: How many MCP packages publish verified provenance →
Install scripts 1 script
| Hook | Tier | Command |
|---|---|---|
| build_backend | allowlisted | setuptools.build_meta |
Background: Why install scripts are a supply-chain risk →
Dependencies 0 packages
| Packages resolved | 0 |
|---|---|
| Tree resolution | Complete |
Background: SBOMs and build attestations, explained →
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
vizier_check_policy ~63
Check content or parameters against security guardrails (DLP credential/PII leaks, sanctions screening, or circuit breaker loop limits).
| Name | Type | Req | Description |
|---|---|---|---|
| category | string | yes | The policy check category. |
| content | – | yes | Text string, parameters object, or entity name to screen. |
No output schema declared.
No examples provided.
vizier_screen_action ~177
Screen and authorize a proposed AI agent action before execution. Evaluates deterministic policy constraints, DLP leakage, loop prevention, and returns an ALLOW / REVIEW / BLOCK decision with an auditable cryptographic receipt.
| Name | Type | Req | Description |
|---|---|---|---|
| action_type | string | yes | Category of action: 'tool_call', 'shell_command', 'payment', 'database_write', 'external_api', 'file_modification', or 'mcp_proxy'. |
| agent_id | string | – | Identifier of the agent requesting action. |
| parameters | object | – | Arguments or payload of the proposed action. |
| principal_id | string | – | Identifier of the human operator or principal. |
| target | string | yes | Exact target resource URI or identifier (e.g. 'mcp://github/create_issue', 'stripe://charges', 'bash://rm', 'https://api.example.com'). |
No output schema declared.
No examples provided.
vizier_verify_receipt ~96
Verify a cryptographic receipt or audit proof issued by Vizier. Validates token structure, expiration, and exact request/action hash binding.
| Name | Type | Req | Description |
|---|---|---|---|
| expected_action_type | string | – | Optional expected action type to verify against the receipt. |
| expected_target | string | – | Optional expected target URI to verify against the receipt. |
| receipt | string | yes | The receipt token string (JWS compact or receipt JSON) issued by Vizier. |
No output schema declared.
No examples provided.
What is the Vizier Guard MCP server?
Vizier Guard is an MCP server listed in the public MCP registry as io.github.vassiliylakhonin/vizier-guard. Deterministic authorization and security guard for AI agent actions with signed receipts. This page covers its PyPI package (vizier-guard).
Is the Vizier Guard MCP server safe to use?
Vizier Guard scores 72 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 20 September 2026. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Vizier Guard MCP server expose?
Vizier Guard exposes 3 tools: vizier_screen_action, vizier_verify_receipt, vizier_check_policy. Their descriptions and schemas cost roughly 336 tokens of context every time the server is loaded.
Is the Vizier Guard MCP server still maintained?
Vizier Guard is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What licence is the Vizier Guard MCP server under?
Vizier Guard declares the Apache-2.0 licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.